Reconsidering Adhesion and Bounce of Submicron Particles Upon High-Velocity Impact

Figures & data

FIG. 1 Relationships between impact velocities (V_i ) and particle sizes (D_a or D _va) for various particle impact phenomena (based on the paradigm originally proposed by Klinkov et al. [2005]). Extreme regimes include erosion, cold spray, and hypervelocity impacts (Klinkov et al. 2005). Particle geometric diameters for each phenomena given in Klinkov et al. (2005) are converted to D_a by assuming that particle density is 1.5 g cm⁻³. The impact velocity-size relationships in AMS (black circles), MOUDI (open circles), and ELPI (gray circles) systems are shown as examples. Data for AMS, MOUDI, and ELPI were taken from Takegawa et al. (2005), Marple et al. (1991), and Keskinen et al. (1992), respectively. For MOUDI and ELPI, particle diameters correspond to the 50% cut point D_a at each stage in MOUDI and ELPI. The area enclosed by thick dashed black lines corresponds to the regime of the aerosol sampling techniques (e.g., Aerodyne AMS).

FIG. 2 V _iy calculated for the impact of NaCl particles on the W surface as a function of their yield stresses.

TABLE 1 COR predicted by the T1990 model as a function of σ_y

Yield stress	Predicted
σy (GPa)	COR
0.02	0
0.1	0
0.5	0.015
1.0	0.154

TABLE 2 Summary of the hydrodynamic simulations of liquid and solid particle impact

	Conditions			Results
	Vi	σy			ΔT max	Fracture ^b
Run ID	(m s^–1)	(GPa)		COR	(°C)	(%)	Note ^a
AN_case1	90	–	–	0	∼0	–	Liquid particles
NaCl_case1	90	1.0	0.2	0.516	124	0.4	Anisotropic elasticity
NaCl_case2	90	0.5	0.2	0.112	64	1.1	Anisotropic elasticity
NaCl_case3	90	0.1	0.2	0	12	3.8	Anisotropic elasticity
NaCl_case4	90	0.02	0.2	0	2	26.8	Anisotropic elasticity
NaCl_case5	180	1.0	0.2	0.018	128	3.0	Incident velocity
NaCl_case6	90	1.0	0.01	0.004	10	2.3	Brittleness
NaCl_case7	90	0.5	0.01	0.039	20	4.6	Brittleness

FIG. 3 A qualitative description of the stress-strain characteristics (von Mises model) used in the AUTODYN simulations.

FIG. 4 Simulation results of the AN particle impact for the case of AN_case1. (a) The temporal evolutions of KE (black line) and IE (gray line) of the AN particle. (b) Pressure and temperature distributions of the AN particle and W surface at t = 1.0 ns.

FIG. 5 Simulation results of the impact of NaCl particles. (a; left panel) Temporal evolutions of fractional contribution of KE (thick solid lines) and IE (thin dashed lines) for the cases NaCl_case1 (σ_y = 1.0 GPa). (a; right panel) Temporal evolutions of fractional contribution of ThW (thick solid lines) and IE_P (thin dashed lines) for the cases NaCl_case1. (b; left panel) Temporal evolutions of fractional contribution of KE (solid lines) and IE (dashed lines) of the NaCl particle for the cases NaCl_case3 (σ_y = 0.1 GPa) (black) and NaCl_case4 (σ_y = 0.02 GPa) (shaded). (b; right panel) Temporal evolutions of fractional contribution of ThW (thick solid lines) and IE_P (thin dashed lines) for the cases NaCl_case3 (black) and NaCl_case4 (gray).

FIG. 6 Simulated profiles of (a) pressure, (b) temperature, (c) effective plastic strain, and (d) material status at t = 0.25 and 1.0 ns for the case of NaCl_case1 (σ_y = 1.0 GPa). The black area in the material status map is defined as the region that underwent failure due to large deformations.

FIG. 7 Simulated profiles of (a) pressure and temperature, and (b) effective plastic strain and material status at t = 1.0 ns for the case NaCl_case4 (σ_y = 0.02 GPa). The black area in the material status map is defined as the region that underwent failure due to large deformations.

FIG. 8 Dependence of COR on σ_y calculated using AUTODYN and T1990 model. Filled markers indicate the AUTODYN simulation results assuming 0.2 of

(circles for 90 m s⁻¹ of V_i and a square for 180 m s⁻¹ of V_i ). Open circles indicate the AUTODYN simulation results assuming 0.01 of 

. Triangle and inverse triangle makers indicate the T1990 simulation results assuming 90 and 180 m s⁻¹ of V_i , respectively. The number in square brackets indicates the crystal surface direction approximately corresponding to the values of σ_y assumed in the simulations.

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